The airwaves may be crowded with wireless signals, e.g., cellular signals, Wi-Fi signals, and/or other wireless signals. Accordingly, radio receivers may need to tolerate large blocker signals, e.g. unwanted signals that may interfere with a wanted signal. In addition, during down-conversion in a receiver, reciprocal mixing of the phase noise of a local oscillator (LO) with an unwanted blocker signal may deposit additive noise on top of the wanted signal. The undesirable effects of reciprocal mixing can be mitigated, in some instances, by filtering the unwanted blocker signal prior to down-conversion using sharp radio frequency (RF) filters. However, the addition of those RF filters may come at the expense of power, cost, and/or area. The undesirable effects of reciprocal mixing may also be mitigated by implementing oscillators that have minimal phase noise, such as LC-oscillators. However, the phase noise improvement of an LC-oscillator may also come at the expense of power, cost, and/or area.
The need exists for a low cost reciprocal mixing noise cancellation technique that has a potential for substantial reciprocal-mixing noise figure improvement independent of the LO phase noise.